Alpha Gruis

Alpha Gruis
Location of α Gruis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Grus
Pronunciation /ælˈnɛər/[1]
Right ascension 22h 08m 13.98473s[2]
Declination −46° 57′ 39.5078″[2]
Apparent magnitude (V) +1.74[3]
Characteristics
Spectral type B6 V[4]
U−B color index −0.47[3]
B−V color index −0.13[3]
Astrometry
Radial velocity (Rv)+11.8[5] km/s
Proper motion (μ) RA: +126.69[2] mas/yr
Dec.: −147.47[2] mas/yr
Parallax (π)32.29 ± 0.21 mas[2]
Distance101.0 ± 0.7 ly
(31.0 ± 0.2 pc)
Absolute magnitude (MV)−0.721±0.031[6]
Details
Mass3.82[7] M☉
Radius3.7[8][a] R☉
Luminosity520[9] L☉
Surface gravity (log g)3.76±0.11[10] cgs
Temperature14,245±484[7] K
Metallicity [Fe/H]−0.13±0.02[11] dex
Rotational velocity (v sin i)215[12][7] km/s
Age100[13] Myr
Other designations
Al Na'ir, α Gru, CD−47°14063, FK5 829, GJ 848.2, HD 209952, HIP 109268, HR 8425, SAO 230992[14]
Database references
SIMBADdata

Alpha Gruis is the brightest star in the southern constellation of Grus. It is officially named Alnair;[1] Alpha Gruis is the star's Bayer designation, which is Latinized from α Gruis and abbreviated α Gru. With an magnitude of 1.74, it is one of the brightest stars in the sky and one of the fifty-eight stars selected for celestial navigation. Alpha Gruis is a single, B-type main-sequence star located at a distance of 31 pc.

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